When I start Visual Studio, it prompts me to upgrade, and when I do, I get an error message that says "Error installing application." It looks like this:
Solution:
Remove incorrectly installed Visual Studio from your Application Folder.
Drag the application from your Applications folder to the trash. If prompted, enter your password and click OK. This doesn't erase the tiny preference files that applications place in your system, so continue below to learn how to thoroughly uninstall a program.
Solution: Remove incorrectly installed Visual Studio from your Application Folder.
https://answers.unity.com/questions/1503339/error-installing-application-when-updating-visual.html